add cached attribute to mockdbcall

[sgsharma]

Fixes # .

Change summary:

• Adds an attribute to the mock DB call for getDiscounts. The reason for this is to improve the demo flow to jump from the DB query exploration to cache and cachesize.

Remaining issues / concerns:

[puckpuck]

I feel like the value should change based on the condition of how mockDBCalls is being called. If we are doing more than 1 call in the loop, the flag should indicate an issue with the cache during that loop.

[puckpuck]

Closing this in favor of upcoming demo changes